YEREVAN -- A U.S. mediator says that the Nagorno-Karabakh conflict has entered a "new phase" after Armenian officials and fellow mediators from France and Russia discussed the issue in Yerevan.

Deputy Assistant Secretary of State Matthew Bryza told RFE/RL's Armenian Service in an exclusive interview that "we need to capitalize" on the progress being made because there is "quite a bit of momentum" as discussions move to Stepanakert, the capital of the unrecognized breakaway republic, and Baku in the next week.

Bryza, who is the U.S. co-chair of the Organization for Security and Cooperation in Europe's Minsk Group attempting to mediate a solution to the conflict, said Armenian President Serzh Sarkisian and Azerbaijani President Ilham Aliyev plan to meet on the sidelines of a May 7 European Union summit in Prague.

Aliyev said in Russia on April 17 that he hopes the Karabakh conflict will be settled "rather quickly," and added that "questions that previously seemed hard to solve have been agreed" upon.

Bryza has been engaged in shuttle diplomacy between Armenia and Azerbaijan for the past few weeks in an effort to gain an Armenian-Azerbaijani framework agreement.